Trigger mechanism for machine guns



Dec. 3, 1929. c. PFEIFFER ET-AL.

TRIGGER MECHANISM FOR MACHINE GUNS Filed Deo- 14. 1928 n n Irltn s' Il V Patented Dec. 3, 1929 UNITE CHRISTIAN IPFEIFFER, F HARTFORD, AND FREDERICK T. MOORE, 0F EAST'HARTFORD, CONNECTICUT, ASSIGNORS TO COLTS PATEN T FIRE ARMS MANUFACTURING C0., OF HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT TRIGGER MECHANISM FOR MACHINE GUNS Application filed December 14, 1928.

The general object of the invention is to provide an improved trigger mechanism which is so constructed as to prevent auton matic continuous firing of the gun and which requires the trigger to be separately moved for the firing of each shot. More specific objects of the inventions are to provide certain novel and improved details of construction whereby the foregoing general object is attained.

The invention is particularly applicable to firearms of the type set forth in the patents to J. M. Browning No. 1,525,065 and 1,525,066 both dated February 3, 1925 and in the accompanying drawings we have illustrated the inventions as applied to a firearm of this type. It will be understood, however, that the drawings are intended for illustrative purposes only and are not to be construed as defining or limiting the scope of the invention, the

claims forming a part of this specification being relied upon for that purpose.

Of the drawings:

Fig. 1 is a fragmentary vertical longitudinal sectional view of a firearm embodying the invention.

Fig. 2 is an enlarged fragmentary longitudinal sectional view showing the trigger mechanism in a position different from that shown in Fig. 1.

Fig. 3 is a view similar to Fig. 2 but showing the parts of the gun in a still different position.

Fig. 4 is a fragmentary plan view of the parts shown in Figs. 2 and 3 the position of the parts, however, being as shown in Fig. 1.

Figs. 5 and 6 are plan and side views respectively of parts of the trigger mechanism separated from other parts of the gun.

Fig. 7 is a front view of the parts shown in Figs. 5 and 6 this view being partly in section along the line 7 7 of Fig. 6.

Fig. 8 is a fragmentary perspective view of the parts shown in Figs. 5 to 7 together with immediately associated parts of the firearm.

In Fig. 1 we have illustrated a portion of a gun of the type set forth in the before mentioned Browning patents. Reference can be had to the said patents for a detailed description of the gun mechanism. For present pur- Serial No. 325,956.

poses it is sufficient to point out that the gun comprises a main casing l generally rectangular in cross section, and a lock frame or member 2 which is longitudinally reciprocable in the casing, this member moving rearward upon recoil and automatically returning toits normal forward position after recoil.` Carried by the reciprocable member 2 so as to be bodily movable therewith is a trigger lever or operating element 3 and also carried by the reciprocable member 2 is suitable mechanism operable when the said member is in its forward position for effecting the firing of the gun upon the movement of the said operating element 3 relatively to the reciprocable member. As shown, the operating element 3 is pivoted at l for rearward movement to effect the .firing of the gun, but we do not necessarily limit ourselves to an operating element which is so movable.

Movably mounted on the casing 1, preferably at the top thereof, is a trigger bar 5 and when the operating element 3 ismovable rea-rwardly to effect firing the trigger bar 5 is also movable rearwardly so as to be adapted to cause the required rearward movement of the elementI 3. As shown the trigger bar 5 is mounted for longitudinal movement and is operatively connected at the rear with a trigger 6 pivoted to the top wall of the casing 1 for movement about a vertical a-Xis. The trigger bar 5 has an upward extension 5a which projects int-o a slot in the trigger. A transverse pin 7 secured to the extension 5UL prevents the rear end of the trigger bar from dropping down. As shownmost clearly in Fig. 8 the forward end of the trigger bar 5 is normally supported directly upon an inward extending flange 8 of the main casing 1, this flange having a` longitudinal groove 9 into which projects a tongue 10 on the left hand part of an enlarged head 11 formed on the bar 5. 1 so located as to engage the upper end of the operating element 3 when the trigger bar is moved rearward, this relationship of the parts being clearly shown in Fig. 4. From the foregoing description it will be apparent that when the trigger 6 is moved rearward the trigger bar 5 is similarly moved rearward,

The right hand part of the head 11 is y the right hand portion ot the head 11 engaging the operating` element 3 to move it backward and thus etteotthe firing of the gun.

In the construction as shown in the Browning patentsreterred .to Continuous or volley .tiringot the ,gun may be caused'bymerely holding the trigger and trigger bar in their rearmost positions. rEhe reciprocable element 2 andal'l ot' the p arts Carried thereby move rear- :some ieircumstanees but under lother oireum-v :stances it is preferable to place the .tiring en tirely -nnder the control :et the and to so eonstrnet and Varrange the parts that the of the `5 f ward position.

tiringiot :each v:shot `@an Ybe ieeet-ed only by a yseparate movement oi 'the trigger. A

dnacoordanee with .fthe invention we providear means dependent lupo-n the movement igger in the 4tiring direction, ordinarily in the `rearward direct-ion, for eiieeting -a 'tnansyerse movement ot the trigger bar 4or at least of the por-tion 11 there-ot vwhichV engages thev operating element. AThis engaging portion 11 is moved transversely out. it the of V-operating element :so Vthat the said eleminut'is not engaged when it .return-s .te itstor- As illustrated there provided a braelret 12 which is secured to the itl/ange S :and which is formed with -a lug 13 havingia ibevzelled cam ,surface 14 adapted to engage a similar cam surface 15 Vonthe left handjpartuoi the head 11. 1t 4will be obvious that :as the trigger har -i-s inoved rearward the surface 1-5 enga-ges the surface 14 with the result thattlv e torwardportion oit the trigger hars Gamm-ed upwardto the position shown in Fig. :2. A par-.t vof* :the rear portion ot the triggerbar is ont away for 'relieved at 16 tov :permit this :up-ward swinging ot the t'oijward pontion ot. the bar. l

lin 'orde-r to holdthe trigger bar ont of the path ot movement oit .operating :element idiuri'ng :the :return movement of the bar in the torward direction we provide a plunger `17 whiohi-s slidably mounted in .a suit-able hole .in the bracket 12 and which is normally f pressed laterally toits outer-position by means of a spring; 18.l Thev plunger is prowdded with a ledge'19 which is automatically pushed under the lett lhand edge part- 11a zot. the head 11 as soon as the sai-d head f beenisuiiieiently raised by `means oit the .cam

surfaces 141- -and v15V as already described.. This ledge Y19 on the plungeri(- serves to support l'the trigger barduring its forward return movement. Y

At the conclus-ion et vits forward movement the head 11 passes beyond the ledge 19 on the plunger 17 andi'sthus reeto return downward to its normal position. In order to positively ensure the downward movement ot the head 11 there is lprovided a spring pressed plunger -i's provided with abevelled surface 21 which is adapted to engage the said ledge 19 and to-ree the plungerinward in opposition to its spring.l 1 1 Y F rom the v`tor-egoing desoriptionitwillbe apparent that whenthe .trigger barV 5 is moved rearward kin 'the Ausual wayl Yby the trigger 6, the forward end of the bar includ- Aing tlie'head 111s raised by the A@am `:surfaces 111 and 15 and that .during this rearwardmovement :the :two Lplnngers 17 Yand20 are forced inward in' vopposition to their'respeotive springs. As soon as .the head l'lpislsueiently raised the ledge '19 on the plunger V17 .snaps -u-nder part .11a rotv the head 11,'f'thus positively holding the trigger bar in its upper position. rThe head 11is so held during the forward re- A:turn movement of the trigger bar, but as the bar .approaches itstorward position it is released by the ledge. 19 and is then 'ii-forced downward by the plunger 20. 'Thus'the vforward .portion of the triggerbar isheld in its :upper positionxout ot the path ot movement of the operating element 3 when at .or near its rearward position. f lt eanbe lite-engaged with the element 3 only lby kbeing first moved VforwardlyA .suiiieiently to be disengaged by the ledge 19. It therefore tollowsthzat thegun can be tired only by effecting .a complete movenient of the trigger and associated parts and Cannot bepred continuously by merelyholdthe 'trigger in its rearward position.

In order to ,positively assurethe upward g a movement of the trigger lbar vsuthoiently lto permit its .engagement by the ledge '19 we prefer to'provide auxiliary Vmeans carried by the reciproca-ble member A'for positively causing the said upwardinovement.- As shown all() this 'means iis in the form Iota cam '22 securedV as a matter of eonvenieneeto the carrier cam 23' whichy is rigidlyl connected with the said `reciprooable memberQ. 'The Cam 211s so positioned as'to engage the :right hand Apart a Y ofthe head 11 and to positively torce it 'upward as clearly'indioated in Fig. From the foregoing description it will be apparent that Yeven it the operator should fail tomove the trigger barfrearwardsuilieiently to .oause the i tudinally reciprocable member movable rearward upon recoil and automatically returning to its normal forward position, an operating element bodily movable with the said member and also movable relatively thereto, mechanism operable when the reciprocable member is in its'forward position for firing the gun upon the relative movement of the operating element, a trigger bar manually movable from its normal position and having a portion adapted upon such movement to engage and move the operating element to iire the gun, means dependent upon the said move- 1 ment of the trigger bar for effecting a transverse movement of at least the said engaging portion thereof out of the path of movement of the operating element,and automatically operative means for holding the said portion out of the said path during the return movement of the trigger bar to its normal position.

2. A trigger mechanism as set forth in claim l, wherein the operating element. and the trigger bar are both movable in the rearward direction to effect firing.

3. A trigger mechanism as set forth in claim l, wherein there is provided a stationary inclined cam surface adjacent the engaging portion of the bar and serving to effect the said transverse movement thereof, and wherein there is a spring-pressed plunger engaging t-he bar to oppose the said transverse movement and to return the bar to normal position at the conclusion of the return movement thereof.

4. A trigger mechanism as set forth in claim l, wherein the said automatically operative means is a transversely movable plunger spring-pressed toward its operative position, and wherein there are means dependent on the firing movement of the bar for forcing the plunger backward in opposition to its spring.

5. A trigger mechanism as set forth in claim l, wherein the said automatically operative means is a transversely movable plunger spring-pressed toward its operative position, and wherein the trigger bar is provided with a cam surface engaging the plunger to force it backward in opposition to the spring during firing movement of the bar.

6. In a triggermechanism for a semiautomatic gun, the combination of a longitudinally reciprocable member movable rearward upon recoil and automatically returning to its normal forward position, an operating element bodily movable with the said member and also movable rearward relatively thereto, mechanism operable when the reciprocable member is in itsforward position for firing the gun upon the relative rearward movement of the operating element, a trigger bar manually movable rearward from its normal `position and' having a portion adapted upon such movement to engage and move the operating element to fire the gun, zi-stationary cam serving during rearward movement of the trigger bar to effect a transverse movement of at least the said engaging portion thereof out of the path of movement ofthe operating element, a spring-pressed plunger for holc ing the Vsaid port-ion out of the said path during the return movement of the trigger barto its normal position,`

means dependent on the rearward movement of the bar for forcing. the plunger backward `in opposition to its spring, and a second spring-pressed plunger acting in a direction at a right angle to that of the first plunger for engaging the trigger bar to oppose the transverse `movement thereof and to return the bar to normal position at the conclusion of the forward return movement thereof. p

7. In a trigger mechanism for a semiautomatic gun, the combination of a longitudinally reciprocable member movable rearward upon recoil and automatically returning to its normal forward position, an operating element bodily movable with the said member and also movable relatively thereto, mechanism operable whenV the reciprocable member is in its forward position for firing the gun upon the relative movement of the operating element, a trigger bar manually movable from its normal position and having a portion adapted upon such movement to engage and move the operating element to fire the gun, means dependent upon the said movement of the reciprocablemember during recoil for insuring a transverse movement of at least the said engaging portion of the trigger bar out of the path of movement of the operating element, and automatically operative means for holding the said portion out of the said path during the return movement of the trigger bar to its normal position.

8. A trigger mechanism as set forth in,

claim 7, wherein the operating element and the trigger bar are both movable in the rearward direction to effect firing.

9. A trigger mechanism as set forth in claim 7 wherein the operating element and the trigger bai are both movable in the rearward direction to effect firing, and wherein the said means for insuring transverse movement is a cam secured to the reciprocating member and directly engaging the trigger bar.

10. In a trigger mechanism for a semiaiitomatic gun, the combination of a longitudinally reciprocable member movable rearward upon recoil and automatically return-` --ingtots normal forward position, an operating eieme'nrt bodily movable'with thesaid ilov member andV movable relatively there-.-

to, mechanism operable when the-recipro- D cable'vmember is in its forward position for the gun npon the relativeimovement y fof, the operating element, 'a' trigger bar manunl'lymovable from its normal position and f Villar/inga;'lomtionV adapted upon such movenient towengage and movel the operating element to retlre gum. means dependent upon .the said movement oflthetrigger bar for ef- Vecting a transverse movement v:of at least 'Y i .the said engaging portion thereof. out Vof the .path-.oi movement fof the operating element, means additional to the last aforesaidrmeans .amide-pendent irpon the rearward movement ofthe reciprocable member lfor insuring the said ltransvewse movement of the Lsaid engagingk portion of( I.tb-.e trigger bar :and yauto- -matioally operative lmeans for holding the e :said portion ont of the :saidrpath duri-ng the `the trigger bar to its .return movement of nor-mal position.4

11. zA :trigger mechanism as. set `forth in claim l0 wherein :the operating element and y the triggerbar are both movable n there'ar- Ward direction to lefffeetxiring.

122. A vtrigger mechanism as set forth in Claim l0, wherein the operating elementand the trigger bar are both movable in thefrear A Wand direction to effect firing, and wherein the said additional means for insuring transrok Verseemovemenit is :a cam secured to the re- .ciprooatingmember and: directly engagin the trigger bar.

V'In testimony whereof` we .have hereunto vset .our hands this 12th @lay foi December,

CHRISTIAN PFEIFFER FREDERICK: T. MOORE. 

